Musical instrument



June 6, 1950 FLEURY 2,510,094

MUSICAL INSTRUMENT Filed May '25, 1946 2 Sheets-Sheet 1 Igj 1%. 2"

Inventor 5/) man 0. Fla/RY Qwaoria Wyn we; 3m 1 June 6, 1950 E. o.FLEURY 2,510,094

MUSICAL INSTRUMENT Filed May 25, 1946 2 Sheets-Sheet 2 G u 57 7? 72 56 a5 o 6 6 =$F a4 Aumo T 4 AMPLIFIER llll'wltor Ear/s75 0. F 1. gum

Patented June 6, 1950 UNITED STATES PATENT OFFICE 6 Claims.

This invention relates to musical instruments, and more particularly tomusical instruments op erated by keys. The principal object of theinvention consists in providing a musical tone or note producing unitwhich, when operated, gencrates electrical oscillations of the exactfrequency corresponding to the musical tone or note associated with thekey. These electrical oscillations may then be used to operate anelectroacoustic sound production system.

A further object of the invention consists in providing a unit of thetype mentioned which produces the electrical oscillations by means of areed or flat spring having a natural frequency with which it willoscillate, if receiving impulses either directly or by using itsinertia. The natural frequency of a reed is defined very exactly andtherefore permits to obtain clear tones.

A still further object of the invention consists in making the reedoperative by placing it into a magnetic circuit in alignment with a corecarrying a coil, the said two members serving to close said magneticcircuit completely with the exception of a small gap left between them.Preferably the cross sections of the reed and the core facing each otheron both sides of said gap are approximately the same so that thevibration of the reed will cause a regular or sinusoidal variation ofthe magnetic flux, and of the current induced thereby in the coilcarried by said core.

A further object of the invention consists in providing a musicalinstrument, using the aforesaid units for producing electricaloscillations of a frequency corresponding to a definite musical tone ornote, in which the keys allotted to each musical tone or note areoperating a mechanism provided with a striking member or a mechanismadapted to impart a rapid movement to one of the units, which movementis automatically and suddenly arrested. In the first case the vibrationis caused directly by the impact of said striking member on thevibrating reed, while in the second case the inertia of the reed causesvibration with natural frequency. The movement of the striking member orof the movable member supporting the above described unit may either beproduced by means of a so-called action or it may be produced byattaching the note producing units directly to the keys.

A still further object of the invention consists in providing a volumecontrol of the sound pro duced which may be either mechanical and mayconsist in means for regulating the damping of the oscillations of thereed or may be electrical, the latter method being preferable in casesin which mechanical control entails constructive difficulties or inwhich the sound volume control is intended to be carried beyond thelimits within which mechanical means will operate.

Further objects will be apparent from the following detailedspecification describing several embodiments of the invention. It is tobe understood that these embodiments are examples for illustrativepurposes and are not intended to be limitative. The invention isdescribed in such terms that the expert skilled in this art will readilyunderstand that certain details and constructional features are subjectto change without in any way departing from the invention.

In the accompanying drawings:

Figures 1 and 2 are elevational side and front views, respectively, of asingle tone producing unit according to the inveniton.

Figure 3 is a cross sectional plan view of said unit, the cross sectionbeing taken along the line 33 of Figure 1.

Figure 4 is an elevational side view of one embodiment of the inventionusing the so-called action now used for Striking the piano strings andfor damping the oscillation for operating the tone producing unitsaccording to the invention.

Figure 5 is an elevational side view of a modification of the actionspecially adapted for the purpose in question.

Figures 6 and '7 are elevational side views similar to those of Figures1 and 2 showing units used for the highest tones.

Figure 8 is an elevational side View of the back board of a piano withthe tone producing units shown in Figures 4, mounted thereon.

Figure 9 is an elevational side view of another tone producingarrangement in which no action at all is used, the tone producing unitbeing directly attached to the keys of the piano.

Figure 10 is a diagram showing the general arrangement and the electricconnections of the modification illustrated in Figure 9 or in Figure 5.

Figure 11 is an elevational view of a complete piano, illustrating thearrangement of the main components.

In order to explain the object of the invention in general terms, it maybe mentioned that it is the main purpose of the invention to produceelectrical oscillations corresponding exactly to the musical tone whichis allotted to each key of the piano or other musical instrument. Whilethe keyboard and the operational method of producing music by depressingkeys corresponding to 3 certain notes remains essentially unchanged, theoscillations directly produced by the keys are not sound vibrations butare electrical oscillations which may be reproduced in the usual manherby a loud speaker, by a telephone or the like or may be recorded in thewell known manner. This electrical reproduction method permits a farbetter regulation of the volume of sound deliv-- ered and it may even beused-in the event that music is practicedin such a way that merely theoperator, or a selected number of persons, is enabled to hear the musicproduced; a result which is easily obtained by using earphones.Conversely, a piano of the type described maybe used with a volume ofsound which exceeds by far that which can be produced by 'the'convemtional type of piano, so that music for a large open air audience, dancemusic for open air, or for a plurality of rooms, etc., may be producedindividually without the intermediation of a pub lic address systemwhich, as a rule, is imperfect from a musical point of view.

The main element of the invention consists in the tone producing unitl2, allotted to each key of the piano or other musical instrument, whichreplaces the piano string conventionally used.

This unit consists of a flat spri or d I4 of a predetermined lengthattached to a frame T6 of magneticallypermeable material, which isclosed on three sides and openat the fourth side. This open side ispartly closed by the reed I l and partly by a core 15 "of magneticallypermeable m'ateria'lprojecting from the frame towards the spring. Onlyasmallgap Ill-is left between these two parts. The core may be bevelledso that it tapers toward the edge l8 facing the reed M. The magneticlinesof force arethus concentrated in a zone corresponding to the crosssection of the spring.

'The' reed may, if necessary, be loaded by a weight l9. It is fixed atone end on "the frame [6 by means of a screw 28. A reed or flat springattached at one end has, as well known a very 1 exactly defined naturalfrequency or resonance 7 frequency, determined by its own free length,if not loaded, or'by the distance of the center of gravity of theoscillating system from the point of attachment, if loaded. The reed orspring of each unit is, therefore, so selected that its nat uralfrequency corresponds to that of the musical tone or note to be producedby one key.

The core I5 is surrounded by a coil 22 provided with fine windings, thewire leading toand from said coil being indicated at 23, 24.

The frame is preferably laminated'and 'consists of a large number oflamellae. is magnetized so as to form a magnet.

Said frame tional mechanism, called action, may be used as illustratedin Figure 4. The units 12 may be aligned along the back board 25 of thepiano or other instrument as no resonance board or the like is necessary(see Figures 4 and 8).

These units as is seen' differ as regards the free length or the reedand the length of the frame I 6 varies 'tion of rest by a spring 56.

correspondingly. However, the cores l5 and coils 22 are preferably thesame for all spring lengths.

The conventional action such as shown in Figure 4 need not be describedin detail as the mechanism is identical with the standard mechanism nowused. It comprises the hammer 26, the check El, cooperating with theback stop 28, the Wippen 29, the prolong 30, cooperating with thecapstan screw 31 directly operated by the key lever 32 which forms acontinuation or projection of the key 35 which turns around the balancerail 36.

The damping mechanism again is practically identical with the dampingmechanism as conventionally used and comprises the damper block 39, thehead ll of which is applied against spring i i of the unit I 2, much inthe same way in which it is usually applied against the piano string.

The conventional action now in use which was developed for pianostrings, although suitable to operate units according to the presentinvention may, however, be simplified to a marked degree.

'This simplification is shown in Figure 5 in which the back board doesnot carry the units but is provided with the check All which in thiscase consists of a wedge-shaped member lined with felt .2. It alsocarries a rail M which supports two pivot pins 45, 46. The prolong 48which cooperates with the capstan screw 3! and key lever 32 in the wayshown in the lower part of Figure 4 marked by reference'letter'a, isprovided with two further pivot pins 49, 50, and is linked to the rail al by means or links 5!,52, turning around the pivot pins 59, 50andt5y46.

Thus a lever parallelogram is formed which will keep the prolong 38 inits vertical position while moved by the key. The link 52 may form partof or may be connected with a bracket 5 extending upwardly from thelever parallelogramand carrying the note or tone producer unit I2.

The damping mechanism in this case is operated by the pedal rod 56,which is connected with "pins 58.

'Each action lever 59 carries a damper wire 6| at the end of which thedamper block 62 is attached. The block62 carries the damper head '63made of suitable material such as a piece of fur of piled fabric and thelike which is to be applied against the reed I4 of the unit l2.

The action leverfit is pivoted at 64 on'a stationarysupporting rail (55and is held in its posi- The'supporting rail may project towards thebracket 54, and may be provided with an end surface 6'! whichis parallelto the bracket as. when at rest and is heavily lined with felt 68 inorder to form a back 'stop'for the moving parts of the mechanism.

It will be clear from the above that the downward movement of key causesan upward movement of capstan screw 3i and of prolong 58 which will movethe bracket 54 against the back wall 35. This movement is suddenlystopped by the felt 52 on member the reed M of the unit i2, therefore,starts its oscillations which will last until the bracket 54 falls back.When the bracket returns the starting of a new "series of oscillationsis effectively prevented by the back stop felt 61.

The oscillations of the reed are effectively clamped by damper head Giheld against the reed 51 is moved and lifts the damper head from thereed M.

A further simplification of the arrangement results if the note or toneproducing units i2 are directly fixed on the keys 35 as shown in Figure9. Preferably the units are fixed on the keys between the keybed frame68 and the balance rail. Each key is, as usual, provided with a stop pin69 striking against a felt pad is on the keybed frame 68. To increasethe force necessary to move the keys and to make it equal to the forcenecessary to move a key against the resistance of the action now in use,th ke levers 32 may be loaded by means of weights (now shown).

The means for translating the electrical oscillations into soundoscillations are shown in Figures and 11. This Figure also shows anelectric volume control of the tones which may be i applied instead ofthe mechanical volume controls produced by damping in those cases inwhich the introduction of a mechanical control entails constructionalcomplications.

In Figure 10, the coils 22 are all arranged in series although otherconnections would be possible likewise. These coils form part of acircuit 10 which may or may not be provided with an amplification stageand which is closed by the step up transformer ii. The secondary 72 ofthe transformer is connected in series with two resistances l5 and whichare provided for volume control purposes. The entire circuit I! containing the said elements forms the input circuit of an audio amplifier78 having as many amplification stages as the purpose of the instrumentmay require. The output circuit 19 of said amplifier is connected withthe voice coil 8| of the loud speaker 80.

The two resistances l5 and 16 have parallel circuits 82, 83 by means ofwhich they may be short circuited. One of these circuits 83 may bepermanently closed by means of the contacts 84 of the pedal 85. Thesecond circuit 82 is open at the contacts 81 as long as the loud pedalis not operated.

A sustaining pedal may be used in addition if, for instance, anarrangement similar to that shown in Figure 5 is employed. In this casethe sustaining pedal may operate the pedal rod 56.

It will be clear that the oscillations produced by the depression of akey of the instrument will induce currents in coils 22, the voltage ofwhich is stepped up in the transformer while currents are magnified bythe amplifier or amplifiers used. These currents act on the loud speakerBB. They have to pass resistance 15 while resistance is normally shortcircuited. If the forte or loud pedal 86 is operated it closes a shortcircuit around resistance 15 and no resistance is then included in theinput circuit of the audio amplifier 18. The notes produced will,therefore, have maximum volume. If soft pedal 85 is pressed the shortcircuit to resistance 76 is interrupted and this resistance is nowactive in series with resistance 15. The volume will, therefore, be outdown to a minimum.

The amplifier or amplifiers may be supplied with current from anysuitable source of electrical energy, a plug connection 88 being shownfor this purpose.

The piano equipped with the tone or note producer units may haveapproximately the shape of a conventional piano. Figure 11 shows theoutline.

The speaker may be arranged in the center of the back wall or in thecenter of the front wall above or below the key frame, the latter casebeing shown in the Figure. The audio amplifier i8 is best arranged onone side with its front wall carrying the switch 96 and the mainadjustment control 9| projecting outwardly. The adjustment control hasonly to be operated occasionahy and readjustment is Only necessary atlong intervals, or with a change of the use to which the instrument isput. The switch 98 has to be operated before use of the piano. The plugin contacts 93, 94 may be used for earphones or for the connection ofthe piano with a distant speaker.

It will be clear that the quality of the music instrument may beimproved in many ways, if desired. For instance, if it is desired toproduce not only the basic musical note but also certain harmonics aplurality of juxtaposed units or of juxtaposed reeds and coils may besubstituted for the single unit.

Moreover, it will be clear that the mechanical and electrical details ofmechanisms have been specifically described merely in order to be ableto illustrate the principles by means of specific examples, but, as itis the principle which constitutes the invention, these specific detailsmay be replaced by others without in any way affecting the invention.

I claim:

1. A device for use in musical instruments for producing musical tonesby means of electrical oscillations, comprising a key, a unit for translating mechanical oscillations of a frequency corresponding to thefrequency of the musical tone to be produced into electricaloscillations, said unit including a frame of magnetized ferro-magneticmaterial open along one side, a magnet core with a reduced substantiallylinear and face, a flat strip-like transversely oscillating reed withone freely oscillating and one fixedly supported end of a predeterminedfree length corresponding to a predetermined natural frequency oftransverse oscillations, having a substantially linear end face at itsfree end, said magnet core and said transversely oscillating reed beinglongitudinally aligned and being mounted on opposite sides of saidframe, projecting towards each other along the open side of the saidframe and substantially closing the open side of the frame, with theirsubstantially linear end faces facing each other across a narrow gap, acoil mounted on said ma net core with its longitudinal axis extendingalong the axis of said core for producing currents induced by thevariation of the magnetic fiux through said core, means operated by thekey for moving said unit, a fixed member for arresting said movement andfor causing an impact producing a vibration of the reed with its naturalfrequency and an electro-acoustic translation means for translating theelectrical oscillations into sound oscillations.

2. A device for use in musical instruments for producing musical tonesby means of electrical oscillations, comprising a key, a unit fortranslating mechanical oscillations of a, frequency corresponding to thefrequency of the musical tone to be produced into electricaloscillations, said unit including a frame of magnetized ferro-magneticmaterial, open along one side, a magnet core with a reducedsubstantially linear end face, a flat strip-like transverselyoscillating reed with one freely oscillating and one fixedly supportedend of a predetermined free length corresponding nerd-cs4 to apredetermined natural frequency 'of transverse oscillations, having asubstantially linear end face at its free end, said magnet core and saidtransversely oscillating reed being longitudinally aligned and beingmounted on opposite sides of said frame, projecting towards each otheralong the open side of the said frame and substantially closing the openSide of the frame, with their substantially linear end faces facing eachother across a narrow gap, a coil mounted onsaid magnet core with itslongitudinal axis extending along the axis of said core for producingcurrents induced by the variation of the magnetic flux through saidcore, means operated by said key to impart a rapid motion to said unit,means to arrestsaid motion to cause the reed to oscillate with itsnatural frequency, and an electro-acoustic translation means fortranslating the electrical oscillations into sound oscillations.

3. A device for use in electrical musical instrumerits, producingelectrical oscillations corresponding to a musical tone comprising amagnetized frame of ferro-inagnetic material open along one side, amagnet core with a reduced substantially linear end face, aflat,strip-like, transversely oscillating reed with a freely oscillating anda fixedly supported end of a predetermined free length corresponding toa predetermined natural frequency of its transverse oscillations, saidreed having a substantially linear end face at its free end, said magnetcore andsaid transversely oscillating reed being longitudinally alignedand being mounted and projecting from opposite sides of the frame towardeach other along the openlside of the saidframe, so as to substantiallyclose said open side, with the substantially linear endfaces of the coreand the free end of the reed facing each other across a narrow gap, acoil on said magnet core with its longitudinal axis extending along saidcore for producing electrical oscillations and mechanical means forproducing a vibration of the reed with its natural frequency.

4. A device for use in musical instruments producing musical tones bymeansof electrical oscillations comprising a unit for translatingmechanical oscillations of a frequency corresponding to the frequency ofthe musical tone to be produced into electrical oscillations, said unitincluding a frame of magnetized ferro-magnetic material, open along oneside, a magnet core with a reduced substantially linear end face, a flatstrip-dike transvcrseiy oscillating reed with a freely oscillating endand a fixedly supportedend of apredeterminedfree length, correspondingto a predetermined natural frequency of its transverse oscillations,having a substantially linear end face at its free end, said magnet coreand said transversely oscillating reed being longitudinally aligned andbeing mounted on opposite sides of said frame, and projecting towardseach other along the open side of the said frame, said core and saidreed substantially closing the open side of the frame with theirsubstantially linear end faces facing each other across a narrow gap, acoil mounted on said magnet core with its longitudinal axis extendingalong the said core for producing currents induced by said core, a key,carrying said unit, said unit being fixedly attached to said key, withthe reed in substantial parallelism to said key, means for arresting'themovement of said key, to produce an oscillation of the reed by inertiaupon arrest of the key and an electro-acoustie translation means fortranslating the electrical oscillations into sound oscillations.

5. A device for use in musical instruments for producing musical tonesby means of electrical oscillations comprising a key, a unit fortranslating mechanical oscillations of a frequency corresponding tothefrequency of the musical tone to be produced into electricaloscillations, said unit including a frame of magnetized ferro-magneticmaterial open along one side, a magnet'core with a reduced substantiallylinear end face, a fiat strip-like transversely oscillating'reed with afreely oscillating nd and a fixedly supported end of a predeterminedfree length, corresponding to a predetermined natural frequency of itstransverse oscillations, having a substantially linear end face at itsfree end, said magnet core and said transversely oscillating reed beinglongitudinally aligned and being mounted on opposite sides of saidframe, projecting towards-each other along the open side of said. frameand substantially closing said openside, with the substantially linearend face of the core-and the free end of the reed facing each otheracross a narrow gap, a coil mounted on said magnet core with itslongitudinal axis extending along said corefor producing inducedcurrents, a rigid backboard, a support for said unit pivoted to saidrigid backboard, a mechanical link connection between said pivotedsupport and said key, adapted to produce a motion of said pivotedsupport towards said fixed backboard, cushioning means on the latterarresting the movementof the pivoted support, a further rigid support,forming a rest for the sup port of the unit, damping means appliedagainst the reed in the position of rest, said means being pivotallymounted on said further rigid support, a pedal and means for connectingsaid pivoted damping means with saidpedal.

6. A musical instrument provided with a number of devices according toclaim 1 whereinthe electro-acoustic translation device includes tworesistances arranged in series, shunt circuits across each of saidresistances, and two pedals, each provided with a contact forcontrolling one of said shunt circuits.

EVARISTE O. FLEURY.

REFERENCES CITED fhe following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,929,027 Miessner Oct. 3, 19331,933,297 Miessner Oct. 31, 1933 2,151,021 Frohman Mar. 21, 19392,155,741 Severy "Apr. 25, 1939 2,321,366 Demuth June 8, 1943

